Nuclear magnetic resonance has been shown to be a useful, non-perturbative tool for studying lipid bilayers. However, application to biological membranes has been limited by the broad line widths which are found for these systems. In these respects, biological membranes are similar to solids and methods which have been developed for solid state NMR can be used to study biological membranes. We propose to spin samples at the magic angle and use proton enhanced nuclear induction spectroscopy to obtain resolved NMR spectra for biological membranes. Attention is focused on (1) small proteins and peptides, such as gramicidin, in lipid bilayers and (2) isotopically enriched amino acid residues in the purple membrane of Halobacteria.